AIPMT PRELIMS2009Chemistry-Chemical Kinetics
AIPMT PRELIMS 2009 Chemistry Rate of Reaction MCQ Question
Type: MCQ-conceptual-Medium-Class 12
For the reaction, N₂ + 3H₂ ⟶ 2NH₃, if d[NH₃]/dt = 2 × 10⁻⁴ mol L⁻¹ s⁻¹, the value of -d[H₂]/dt would be:
A
4 × 10⁻⁴ mol L⁻¹ s⁻¹
B
6 × 10⁻⁴ mol L⁻¹ s⁻¹
C
1 × 10⁻⁴ mol L⁻¹ s⁻¹
D
3 × 10⁻⁴ mol L⁻¹ s⁻¹
Correct Answer
Option D
Detailed Explanation
The rate of disappearance of H₂ is related to the rate of formation of NH₃ by the stoichiometry of the reaction. Since 3 moles of H₂ produce 2 moles of NH₃, the rate of disappearance of H₂ is (3/2) times the rate of formation of NH₃. Therefore, -d[H₂]/dt = (3/2) × 2 × 10⁻⁴ = 3 × 10⁻⁴ mol L⁻¹ s⁻¹.
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